Transfer mechanism for digital counter



Feb. 10, 1970 A. sPA'TH TRANSFER MECHANISM FOR DIGITAL COUNTER 3 Sheets-Sheet 2 Filed July 50, 1968 F igffic ALFONS' sPA'TH INVENTOR.

ATTORNEY.

Feb. 10, 1970 A. sPATH 3,494,549

TRANSFER MECHANISM FOR DIGITAL COUNTER Filed July 30, 1968 3 Sheets-Sheet 3 ALFONS sPR'rH INVENTOR ATTORNEY United States Patent 1,54 ,9 Int. Cl. G06c 7/10, 9/00, 15/26 U.S. Cl. 235-439 12 Claims ABSTRACT OF THE DISCLOSURE Transfer pinions for the intermittent coupling of adjacent digit wheels of a digital counter, mounted on a common shaft parallel to the digit-wheel shaft and displaceable relatively thereto in a generally axial direction for disengaging the pinions from the digit wheels preparatorily to a resetting of the latter, have axially projecting polygonal hubs which during all or part of a disengagement stroke rest with one of their sides against a substantially fiat surface of an indexing element extending at right angles to the direction of stroke; a single indexing element may be common to two adjoining transfer pinions by bearing simultaneously upon their aligned hubs.

The present invention relates to a digital counter wherein two or more digit wheels assigned to successive denominational orders (e.g. decades), carrying numerical designations or co-operating with respective indicator elements, are stepped by manual or automatic means acting upon the lowest-order digit wheel (e.g. units stage) which in turn, once per revolution, advances the digit wheel of the next-higher order (e.g. the tens stage), the latter in turn intermittently stepping the wheel of a further order (e.g. hundreds stage) and so on.

The invention relates more particularly to a transfer pinion associated with a pair of successive digit wheels having two interleaved sets of teeth engageable with transfer teeth on a lower-order digit wheel and with stepping teeth on a higher-order digit wheel, the teeth of one set being also adapted to straddle a peripheral surface of the lower-order digit wheel for preventing rotation of the transfer pinion in an engaged position. As disclosed, for example, in US. Patent No. 3,244,368, the two sets of teeth of such transfer pinion may be combined into full teeth and partial teeth following one another in alternate succession along the periphery of the pinion, only the full teeth being wide enough to engage the peripheral wheel surface while the partial teeth stands proud of that surface. Thus, with n full teeth and n partial teeth, the total number of pinion teeth is 2n Where It is an integer preferably equal to 4.

In such a counter it is customary to make the transfer pinion or pinions displaceable, in a generally radial direction, from the axis of the digit wheels in order to facilitate a resetting of these wheels, generally to zero. Upon such decoupling of the transfer pinion or pinions from the associated digit wheels, care should be taken to prevent their spontaneous rotation which could turn some of these pinions into a blocking position in which one of their teeth could interfere with the re-engagement of the digit wheels and the pinions. For this purpose it has already been proposed (see the aforementioned US. Patent No. 3,244,368) to provide a fiat bar extending parallel to the digit-wheel axis across the row of transfer pinions so as to be engageable by confronting sides of square-profiled hubs of these pinions at the end of a decoupling stroke, the width of the hub being so large that the circumference of the pinion teeth falls within the area of the square. According to another solution (see US. Patents No. 1,744,307), a smaller pinion hub of similar square outline slides during the decoupling stroke into lateral engagement with a generally radially extending indexing spring. In either of these cases, the hub of the transfer pinion engages the restraining element (bar or spring) only in a terminal phase of the decoupling stroke so that, unless the element is strongly biased toward the pinion axis, spontaneous rotation of the pinion into a return-blocking position may occur. Such a strong bias, however, would be rather impractical in the case of a radially oriented indexing spring because of the large frictional resistance which would then have to be overcome as the hub slides alongthe spring. In the case of a continuous indexing bar spanning a multiplicity of transfer pinions, the normal separation of this bar from the hub faces must be sufiicient to prevent the hubs from becoming jammed between the digit wheels and the bar when rotating during a transfer operation; this requirement, in turn, involves a somewhat unwieldy construction of the mechanism.

The general object of this invention is to provide a transfer mechanism of the character set forth which avoids the aforestated disadvantages while preventing untimely rotation of the transfer pinion or pinions of a multi-position digital counter.

A more particular object is to provide simple means in such transfer mechanism for normally holding each transfer pinion in close contact with its associated digit wheel so as to insure an accurate indexing of these wheels in their last-selected digital positions with avoidance of ambiguous readings.

These objects are realized, in accordance with the present invention, by the provision of a transfer mechanism of the general character described wherein each transfer pinion or pair of adjacent transfer pinions is as sociated with an individual indexing element having a substantially flat contact surface substantially perpendicular to the generally radial direction of decoupling displacement, the contact surface being yieldably engaged by a parallel side of a hub of polygonal cross-section, projecting axially from each associated transfer pinion, at least during a terminal phase of the decoupling displacement for resisting rotation of the pinion or pinions prior to a separation of the straddling pinion teeth from the peripheral digit-wheel surface to extent suflicient to enable such rotation.

The polygonal (preferably square) hub profile need not be sharply defined but may have rounded corners to prevent abrupt camming of the transfer pinion by the overlying indexing element from one angular position into the next, particularly if the contact surface of this element permanently engages the sub of the pinion. The sides of the polygonal hub may also be concave rather than flat, this being especially desirable where the hub is not in permanent contact With the indexing element since it enables the latter to reorient the transfer pinion in a more effective manner upon engaging its hub. It is also desirable to make the hub and the body of the pinion, especially the teeth thereof, of different materials, the material of the teeth being preferably of reduced friction compared with that of the hub. Thus, known lowfriction materials (e.g. Teflon) may be used for the teeth while the hub is made, for example, of polyamide; naturally, the pinion may also be made of metal.

In principle, the yieldable indexing element may be biased toward the pinion hub by a variety of forces, e.g. resiliency or gravity. Thus, the indexing element may be a spring tongue or, if the direction of the decoupling stroke is generally vertical, a weighted arm. If this indexing element is in permanent contact with the hub of a transfer pinion or-according to an advantageous modification-with a pair of such pinions extending toward each other, no separate restoring means may be needed to maintatin the pinions in their engaged position as long as resetting is not required. A particularly compact assembly is obtained if the hub diagonal is smaller than the pitch diameter of the pinion teeth, with the indexing element disposed between two adjacent transfer pinions.

The invention will be described in greater detail with reference to the accompanying drawing in which:

FIG. la is a cross-sectional view of a digital counter with a transfer mechanism representing a first embodiment;

FIG. lb is a top view of the assembly of FIG. 1a;

FIG. 16 is an elevational detail view of a modification of the arrangement of FIG. 1b;

FIG. 2 is a view similar to FIG. la, illustrating another embodiment; and

FIG. 3 is a further cross-sectional view similar to FIG. 1a, showing still another modification.

FIGS. la and 1b show a counter with four digit wheels 1 (thousands) 2 (hundreds) 3 (tens) and 4 (units). These wheels are mounted on a common shaft 5 on which they are independently rotatable and which is held in side walls 6, 7 of a housing having also a bottom 10 and a rear wall 13 of reduced height. The wheels 1-4 bear the usual numerical markings, i.e. numerals to 9, which may be viewed through a window of a housing cover not shown; it is assumed that this window extends along the top of the housing so that the Wheel position illustrated in FIG. lb gives the reading 0090. Spacer disks 8 and 9 are inserted between the wheel assembly 1-4 and the side walls 6, 7. I

A mounting block 12 rising from the housing bottom 10 has a bore 13 aligned with a bore 13 in rear wall 11, the two bores being traversed by the stem 14 of an actuating knob 15 which is biased outwardly by a coil spring 18; stem 14 also passes through a mounting bar 38 serving to clamp a set of springs 32, 32, 36 and 37 between itself and the wall 11 onto which the bar is held by screws not shown.

The lowest-order digit wheel 4 is integral with a tenteeth ratchet 19 adapted to be rotated, one tooth at a time, by a stepping pawl 16 in the form of a bent leaf spring which is fastened to the inner end of stem 14 by a screw 17. A retaining pawl 21 mounted on a block 20 prevents reverse rotation of the ratchet.

Each of the lower-order digit wheels 2, 3, 4 has a peripheral shoulder 29 carrying a pair of transfer teeth 29a, 29b separated by a gap 290 (visible for the wheel 3 in FIG. 1b), the gap 290 also extending into the adjoining peripheral wheel surface bearing the numerical markings 0 through 9. Three transfer pinions 25, 26 and 27, respectively assigned to the wheel pairs 3/4, 2/ 3 and 1/ 2, are mounted on a common shaft 28 for independent rotation, the extremities of the shaft projecting beyond the first pinion 25 and the last pinion 27 into recesses 39, 40 of housing walls 7 and 6 in which they are guided with freedom of generally radial displacement with reference to a digit-wheel shaft as indicated by an arrow A in FIG. 1a. Such displacement is resisted by the springs 36 and 37 bearing upon these extremities of shaft 28.

As specifically illustrated for the pinion 25 in FIG. la, each of the three pinions 25-27 comprises two interleaved sets of teeth, i.e. a set of full teeth 23a, 23b, 23c, 23d and a set of partial teeth 24a, 24b, 24c and 24d. The teeth of both sets are arranged to mesh with the transfer teeth 29a, 29b of the associated lower-order digit wheel as well as with an array of pegs 22 on the associated higher-order digit wheel, these pegs representing a set of stepping teeth (20 in all) of which seven are shown in FIG la at 22a, 22b, 22c, 22d, 22e, 22 and 22g. The full teeth 23a etc. are wide enough to straddle the outer peripheral surface of the associated lower-order wheel, specifically the digit wheel 4 in the case of pinion 25 as illustrated for the teeth 23c, 23d thereof in FIG. 1a; the partial teeth 24a etc. are of reduced width so as toclear this peripheral surface as illustrated for the tooth 24d.

Pinion 25 has a hub 35 of square cross-section whose diagonal is less than the pitch diameter of the teeth 23a- 23d, 24a-24d, being substantially equal to the root diameter of these teeth in this and subsequent embodiments. In the normal position of this pinion, in which two of its full teeth (23c, 23d) straddle the periphery of digit wheel 4 and the intervening partial tooth (24) projects radially past that periphery, one of the side faces 30 of hub 35 lies fiat against a confronting surface 31 of spring 32, both these surfaces lying at right angles to the decoupling direction (arrow A) represented by a line interconnecting the centers of shafts 5 and 28. Hub 35 of pinion 25 extends axially toward the hub 34 of pinion 26, both these hubs being bridged by that part of indexing spring 34 which extends perpendicularly to the radial direction A. In similar manner, the spring 32' bridges the hubs of pinions 26 and 27. End springs 36 and.37 have active portions parallel to those of indexing springs 32, 32' and may be somewhat stronger than the latter.

In the normal operation of the system shown in FIGS. 1:: and 1b, units wheel 4 is manually stepped in a clockwise direction (as seen in FIG. 1a) by repeated actuation of knob 15 to increase the value of the registered count. In the illustrated zero position of this wheel, its transfer teeth 29a, 29b lie just downstream of pinion tooth 24d in registry with teeth 22a and 22 of tens wheel 3, tooth 24d being flanked by the teeth 22d, 22e of the latter wheel. When, after nine actuations of knob 15, tooth 29]) comes to rest in front of tooth 24d, wheel 4 occupies the position illustrated for wheel 3 to register the value 9. The next actuation of knob 15 causes the teeth 29a, 29b of wheel 4 to entrain the teeth 24d, 23d of pinion 25, the last-mentioned teeth being received in the gap 290 between the two transfer teeth. Pinion 25, in rotating through an angle of imparts a rotation of 36% (in step with wheel 4) to digit wheel 3 to advance the latter to its next angular position which happens to be 0; thus, transfer teeth 29a, 29b of wheel 3 also entrain the pinion 2'6 with a resultant stepping of hundreds wheel 2 into its No. 1 position. The continuous pressure of springs 32, 32' upon the hubs of pinions 25, 26 maintains these pinions in their new angular positions and contributes to the smooth operation of the mechanism.

To facilitate resetting, each of the higher-order digit wheels 1-3 may be provided with a pawl or rack (not shown) engageable with its stepping teeth 22, whereby the wheel is rotated clockwise (FIG. la) into its zero position, the teeth 22 camming the inwardly projecting pinion tooth (e.g. 24d) outwardly to impart fractional counterclockwise rotation to the transfer pinion while a full tooth thereof (such as 23d) bears upon the periphery of the adjacent lower-order wheel; after the higher-order wheel has been reset, spring 32 or 32' cleanly returns the pinion to its illustrated engaged position, the tooth 24d re-entering a gap between two teeth 22. If the lower-order wheel is already in its zero position, its slight displacement by interaction of teeth 24c and 290: will be rectified upon such re-engagernent by the tooth 23c co-operating with tooth 29a.

The corners 22 of polygonal hub 35 are shown to be slightly rounded to reduce the effort of rotataing this hub past the spring surface 31 during a transfer operation.

With the four-stage counter shown in FIG. 1b, two indexing springs 32 and 32 are needed for the three transfer pinions 25-27, pinion 26 being controlled by both indexing springs. If the number of transfer pinions is even (and, therefore, the number of digit wheels is odd), only one indexing spring will be needed for every two transfer pinions.

In FIG. there has been shown a modified spring assembly wherein elements 42, 43, 36 and 37, corresponding to springs 32, 32, 36 and 37 of the preceding embodiment, are integrally interconnected, resilient tongues forming part of a yoke 41 clamped between bar 38 and wall 11. Tongues 42 and 43, bridging again respective hub pairs such as hubs 34 and 35, are of sufiicient width to maintain the necessary spacing between the associated transfer pinions 44, 45, 46 on shaft 28 without the need for additional spacing means. The outer tongues 36' and 37' are bent toward the axis of shaft 28, as indicated at 47, at a sharper angle than the tongues 42, 43 so as to bear upon this shaft for the purpose and in the manner described with reference to FIGS. 10 and 1b.

FIG. 2 shows a generally similar digital counter wherein, however, the manual actuator 14-49 of the preceding embodiment has been replaced by an automatic drive for the units wheel 51 of a set of such wheels of which only the tens wheel 52 is visible; this automatic drive includes a ratchet 56 rigid with the wheel 51 and a double pawl, comparable to the escapement of a timepiece, which may be intermittently or continuously operated (e.g. by an electromagnetic control as illustrated in FIG. 3) to bring about a step-by-step advance of wheel 51 in response to a clockwise driving torque applied, for example, through a wound spring or a slipping clutch to the wheel shaft '53. The housing of the counter, of which only a side wall 54 and a back wall 55 are visible, supports a yoke 64 with lateral arms 63 (only one shown) and a bridge 65, this yoke being swingably mounted on a fixed rod 37 which also serves as a fulcrum for a similar yoke 80 carrying a set of resetting prongs 66. Yoke 64 supports a shaft 62 on which a set of transfer pinions 61 (only one shown) with full and partial teeth 50 and 60 are independently rotatable; these teeth coact with peripheral teeth 58a-58h of wheel 52 and with transfer teeth (not shown) of wheel 51.

The hub 75 of pinion 61 has its upper horizontal side 73 overlain by a substantially flat surface 72 of an indexing element 69 which comprises an arm 70 with a weighted extremity 71 forming the surface 72; the arm is swingably mounted, along with other such arms associated with further transfer pinions, on a rod 68 spanning the yoke 64.

For zero-setting purposes, each of the digit wheels 51, 52 etc. is reset by means of a respective heart cam 74 coacting with one of the prongs 66 when the yoke 64 is swung clockwise about its pivot 67 to decouple each of the pinions 61 from the teeth of the associated digit wheels; yoke 80 may then be swung in the same sense, manually or by other means, to arrest the liberated digit wheels in their starting positions in which the bent extremities of prongs 66 fall into the recesses of the corresponding heart cams 64 as is well known per se (see, for example, US. Patent No. 3,248,051).

In this embodiment, as in the preceding ones, the indexing element again is in permanent contact with the hub of the associated transfer pinion.

FIG. 3 shows part of a modified counter with digit wheels 110 (only one shown) on a shaft 111, a housing 112 supporting this shaft, and a resetting lever 113 cooperating with a heart cam 119 substantially in the manner described with reference to elements 66 and 74 of FIG. 2, lever 113 being swingable about a rod 116 parallel to shaft 111. An extension 115 of lever 113 supports a shaft 114 carrying a set of transfer pinions 118 (only one shown) with hubs 120 which, while also being of basically square cross-section, differ from the hubs of the previous embodiments by having slightly concave sides 123. An indexing element individual to each hub, or to a pair of confronting hubs as previously described, is shown as a flat leaf spring 121 supported on a fixed bar 122.

A control lever 117, linked with extension 115, can be moved downwardly to swing the assembly 113, 114, 115 counterclockwise about its pivot 116, thereby decoupling the transfer pinion 118 from the associated digit wheel 6 and bringing the point of lever 113 into co-operating relationship with heart cam 119. During this decoupling movement the hub 120 approaches the spring 121 so that one of its sides 123 comes to rest against this spring before the full teeth 131 of pinion 118 have cleared the periphery of the associated lower-order digit wheel to an extent sufficient to let this pinion rotate freely, i.e after the pinion has swung downwardly by a distance d less than the extent of radial overlap r between the partial tooth 132 and the digit wheel.

FIG. 3 also shows an electromagnet 103 with a pole shoe 101, a core 102, and an armature 105 supported by a lug 104, the armature 105 engaging a lever 106 integral with a member 107 which may be linked with the escapement 57 of FIG. 2 or otherwise form part of a stepping drive for the counter. Lever 106 is swingable about a pivot pin 108 and is normally held withdrawn by a tension spring 109.

The invention is applicable to all kinds of digital counters, including those specifically illustrated and others with manual or automatic drive, designed to measure a succession of operated cycles of reciprocating or rotating elements.

I claim:

1. In a digital counter having a plurality of coaxially juxtaposed digit wheels of progressively higher denominational orders, including at least one lower-order wheel provided with transfer teeth adjoining a peripheral surface and at least one higher-order wheel provided with a peripheral array of stepping teeth, said counter further having at least one transfer pinion associated with said lower-order and higher-order wheels and provided with two interleaved sets of teeth engageable with said stepping teeth and with said transfer teeth, the teeth of one set being arranged to straddle said peripheral surface for preventing rotation of said transfer pinion in an engaged position, the combination therewith of mechanism for decoupling said transfer pinion from said digit wheels by displacement in a generally radial direction from the axis of the latter, and at least one yieldable indexing element biased toward said axis and provided with a substantially flat contact surface substantially perpendicular to said direction of displacement, each transfer pinion being provided with an axially projecting hub of polygonal cross-section having a side parallel to said contact surface of an associated indexing element in engagement therewith at least during a terminal phase of said displacement for resisting rotation of said transfer pinion prior to a separation of said one set of teeth thereof from said peripheral surface to an extent enabling such rotation.

2. The combination defined in claim 1 wherein the corners of said polygonal cross-section are rounded.

3. The combination defined in claim 1 wherein the sides of said polygonal cross-section are concave.

4. The combination defined in claim 1 wherein the number of said digit wheels is greater than two and the number of transfer pinions is greater than one, the diagonal of said polygonal cross-section being smaller than the pitch diameter of the teeth of said transfer pinions, said indexing element being disposed between two adjacent transfer pinions.

5. The combination defined in claim 4 wherein said indexing element is wide enough to keep said adjacent transfer pinions axially spaced apart.

6. The combination defined in claim 4 wherein the hubs of said adjacent transfer pinions are extended toward each other, said indexing element bridging coplanar sides of both said hubs.

7. The combination defined in claim 4 wherein the number of indexing elements is greater than one, said indexing elements being integrally interconnected resilient tongues.

8. The combination defined in claim 4 wherein said transfer pinions are provided with a common shaft having extremities guided for lateral displacement in said generally radial direction and projecting beyond the first and last transfer pinions, further comprising a spring yoke with a pair of arms bearing upon said extremities for resisting said lateral displacement, said indexing element being a resilient tongue integral with said yoke.

9. The combination defined in claim 1 wherein said indexing element is in permanent contact with said hub.

10. The combination defined in claim 1 wherein said generally radial direction is substantially vertical, said indexing element comprising a swingable arm with a weighted end bearing upon said hub.

11. The combination defined in claim 1, further comprising a frame swingable about a line parallel to said axis and'normally inoperative zero-setting means on said frame, said transfer pinion being mounted on said frame for displacement away from said axis in said generally radial direction and against the force of said indexing UNITED STATES PATENTS 1,370,540 3/1921 Hussey 235-139 1,744,307 1/1930 Gluck 23530 3,050,250 8/1962 Mann 235-144 3,244,368 4/1966 Juhas 235144 3,321,134 5/1967 Sigl 235144 STEPHEN I TOMSKY, Primary Examiner US. Cl. X.R. 235-144 

